The Multiverse is the idea of other universes in a hypothetical larger cosmic space.
EvidenceIn year 2010, concentric circles patterns were found in the cosmic microwave background, the 'echo' of the Big Bang.
"These guys start with a different model of the universe called eternal inflation. In this way of thinking, the universe we see is merely a bubble in a much larger cosmos. This cosmos is filled with other bubbles, all of which are other universes where the laws of physics may be dramatically different from ours. These bubbles probably had a violent past, jostling together and leaving “cosmic bruises” where they touched. If so, these bruises ought to be visible today in the cosmic microwave background." (Quote from an article)